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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=RBcAXdVTzDlQEdHvHcfy5u8SoDIYRNYoD+l06R5dEr8IiRSt1SUOgl5Ln3W1xQkRJ 9LCvLzzfHpYLQdKcNxw+VEwRkSCWnK2rbKwhSJF/OP9srEmBXOU9cpVFjQgZ2KdbvY +4QSQaP3c+8pntVFa6bRe5u7sMIXQwwXCpNoo/BUj/JKLtnZMVuvgmNRoz4SfXLP3r WN07RgB2nY8y6SilloaZLjeVqFfitSLmJzD/FoSlPgrcgfone6fxT1SapYvF9FZ8IJ gREQLWU1DoQzVBwWORiVWI+354MM/fB16oY7FDSXN0u2pRKwtTRGh2uFQvA+SZoOGM 77RAC6TMjYTGA== Date: Thu, 29 Oct 2026 14:22:48 +0100 From: "Oscar Salvador (SUSE)" To: Muchun Song Cc: Kaitao Cheng , Oscar Salvador , David Hildenbrand , Andrew Morton , Baolin Wang , Mike Kravetz , Frank van der Linden , Michal Hocko , Joshua Hahn , Chris Down , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Kaitao Cheng Subject: Re: [PATCH 3/3] mm/hugetlb: fix NR_HUGETLB accounting for unused surplus folios Message-ID: References: <20261028113319.38544-1-kaitao.cheng@linux.dev> <20261028113319.38544-4-kaitao.cheng@linux.dev> <87146009-8E2A-467B-AAFF-8F79E9D5E32F@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87146009-8E2A-467B-AAFF-8F79E9D5E32F@linux.dev> X-Rspam-User: X-Rspamd-Queue-Id: C41DF10000E X-Stat-Signature: 876ibp657f8ix7ejtngaufc98ctf7ejd X-Rspamd-Server: rspam01 X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1793280176-623844 X-HE-Meta: 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 NAF4fWNL QYJW/jP29SX1Nh8mhRStkWWaIErCPMBc7bha/xr83bwYGElpFQuZSMpS/flE0iu7GRZyxrkUI9vm7zWPUhtXX/LhUZ0bVOKXb9TWEsB99uHqhr/OqFr0sZQ6lAz5/EsbUB7cEsJTlh60lA3qhPGTqjgi5UYK9QUNXOWh0vW6hyWnIODeJ3QARMHyJ5ahKHQtDs+0o23AVhu+/S6BSNaUoHCUFRIoit3nKsnsJypN/qUVmq7xiw5EvCeNGhnpPIxI5S31o4EAVfxRUCRSrf+VBdoLo9S0z7+5yCW067qlWnJYR+aQI4kMx5txFsCcYV5VyBwhjR3EcJKG3QNlv9Jn7gT7jsA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Thu, Oct 29, 2026 at 11:21:47AM +0800, Muchun Song wrote: > My thinking is that we should not use lruvec_stat_mod_folio(). Instead, we > should use mod_node_page_state() and mod_memcg_lruvec_state() > independently. In that case, when a new hugetlb page is allocated, we could > account for it directly via mod_node_page_state(). The reason is tha > lruvec_stat_mod_folio() also accounts per-memcg NR_HUGETLB; only by > splitting the two can we minimize the problems introduced by accounting. For > callers that need to consider memcg, mod_memcg_lruvec_state() can be used. Ok, this sounds pretty compeling, and IMHO makes sense. I mean I get the ideabehind this patch but it feels like papering over the real problem. > I expect that after some cleanup, there will be only one place that needs to > handle per-node NR_HUGETLB. > > Thoughts? > > Thanks, > Muchun > > > > I will have another look later on. > > > > > > > > -- > > Oscar Salvador > > SUSE Labs > -- Oscar Salvador SUSE Labs